Automatic stoker



AUTOMATIC STOKER Filed Oct. 25, 193'? Fig. 1

I T J w a 22 2/ /a 22 /4 /4 v 2/ Fig.2.

Patented July 23, 1940 AUTOMATIC STOKER Albert G. Blcdgett, Worcester, Mass, assignor to Riley Stoker Corporation, Worcester; Mass, a corporation of Massachusetts Application October 25, 1937, Serial No. 170,?51

4 Claims.

This invention relates to automatic stokers, and more particularly to the construction and arrangement of an improved fuel feeding mechanism for stokers of the multiple retort underfeed type.

A stoker of this type comprises a series of parallel retorts located within a furnace, ram casings arranged adjacent the front wall of the furnace and communicating with the retorts, and "rams reciprocable within the ram casings to feedfuel rearwardly into the retorts. The ram casings are formed with openings or throats in their upper portions to which fuel is supplied by gravity from a large hopper thereabove. In the past considerable difficulty has been encountered in obtaining the required movement of fuel from the hopper to the ram casings. When a particular ram is in its rearmost position, the corresponding throat is of course blocked thereby, I. and all fuel flow into that particular ram casing is stopped for the moment. Then when the ram is withdrawn forwardly to open the throat, it is often found that the fuel will remain stationary thereabove instead of dropping through the throat as intended, and as the fuel in the corresponding retort is consumed the various metal parts within the furnace will become exposed to the heat, with resultant great damage. This is particularly the case when the fuel is wet or otherwise of a sticky nature.

These difficulties have been widely recognized, and a great amount of inventive effort has been applied in attempts to solve the problem. In many cases agitating mechanisms have been installed in the hopper to stir the fuel and prevent it from lodging. These mechanisms are usually complicated, expensive and subject to rapid wear, and they often fail to ensure the desired regularity of feed. In other cases individual hoppers 40 have been provided for the respective ram casings, but this construction is expensive, inconvenient when adding fuel to the hoppers, and comparatively ineffective for the purpose intended.

It is. accordingly one object of the invention to provide a comparatively simple, inexpensive and reliable apparatus for feeding fuel to the retorts of a multiple retort underfeed stoker.

It is afurther object of the invention to pro- ?vide a single large hopper to supply-fuel by gravity to a plurality of fuel feeding rams, and to construct the various parts in such a manner as to ensure a regular and dependable feed.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in thespecification and covered by the claims appended hereto.

In accordance with my invention in its preferred form, I provide a series of ram casings 5 located side by side, with a fuel feeding ram arranged in each ram casing, the rams being reciprocable in generally horizontal parallel paths. Each ram casing is provided above the ram with a throat opening having two lateral walls, one of these walls extending upwardly from one side of the ram in a substantially vertical plane, and the other extending upwardly from the opposite side of the ram in a plane which slopes at an angle preferably somewhat steeper than the angle of repose of the fuel. The construction is such that the ram is exposed for substantially its full width at the bottom of the throat, and the throat widens gradually and continuously from its lower end to its upper end. The upper edge of each vertical side wall is located close to the upper edge of the inclined side wall of the adjacent ram casing. A single laterally elongated hopper is mounted above the series of ram casings to supply fuel by gravity to the several throats. This construction avoids any horizontal surfaces on which fuel may accumulate to hinder the desired downward flow of fuel, it avoids any undue restriction in the throats, and it greatly decreases the possibility of arch formations in the fuel passing through the throats.

Referring to the drawing illustrating one em-- bodiment of the invention, and in which like reference numerals indicate like parts:

Fig. l is a longitudinal section through the fuel feeding mechanism of a multiple retort underfeed stoker, the section being taken on the line l.-I of Fig. 2; and

Fig. 2 is a section onthe line 2-2 of Fig. 1.

The embodiment illustrated comprises a furnace front wall I!) having a series of openings H therethrough which lead to parallel rearwardly extending retorts (not shown) of well known construction. In front of each opening ll there is mounted a ram casing l2 having a ram I4, slidably supported therein for reciprocation in a generally horizontal path. The several rams are driven in a well known manner by means of a rotatable crank-shaft 15 located in front of the ram casings l2 and operatively connected to each ram by means of a connecting rod [6.

Each ram casing is provided above the ram with a throat it having a rear wall l9, a front wall 20, and twolateral walls 2! and 22. These four walls are preferably integral with the ram casing, which can be readily manufactured in the form of a casting. The rear wall I9 is substantially vertical, and the front wall 20 slopes downwardly and rearwardly at a steep angle. The lateral wall 2| extends upwardly from one side of the ram I4 in a substantially vertical plane, as shown in Fig. 2, and the other lateral wall 22 extends upwardly from the opposite side of the ram in a plane which slopes at an angle sufficiently steep to prevent any lodgment of the fuel. As shown, this wall makes an angle of approximately sixty degrees with the horizontal, whereas the angle of repose of bituminous coal, which is the fuel customarily used in these stokers, is in the neighborhood of forty degrees. Each of the sloping lateral walls 22 is continued upwardly-to a sufficient height to bring its upper edge close to the upper edge of the vertical lateral wall 2| of the adjacent ram casing.

Above the series of ram casings l2 there is mounted a single laterally elongated hopper 24 which serves to supply fuel by gravity to the several throats 8. This hopper comprises a sub stantially vertical rear wall 25, a front wall 26 which slopes at a steep angle downwardly and rearwardly, and two lateral or end walls 2'! and 28. The wall 2'l is vertical, and the wall 28 is likewise vertical except for a downwardly and outwardly sloping lower portion 29. This construction makes it possible to mount an inspection door 3| on the wall ill at each side of the hopper. Directly above the upper edges of. each pair of adjacent lateral walls 2| and 22 of the throats Hi there is mounted a deflector 32 which is secured at its ends, by welding or otherwise, to the front and rear walls 26 and 25 respectively of the hopper. These deflectors are each shaped substantially as an inverted V in cross-section, with one vertical leg overlying the adjacent wall 2| and with one sloping leg overlying the adjacent wall 22. With this construction the hopper is strengthened, and leakage of fuel between'the ram casings is prevented.

The operation of the invention will now be apparent from the above disclosure. The hopper 24 is filled with fuel, which descends by gravity through the throats l8 and is pushed rearwardly through the openings II by the reciprocating rams I4 driven by the rotating crankshaft l5. The hopper is of simple and inexpensive construction, and it can be kept filled readily by means of an ordinary down-spout from an overhead bin. Moreover, since there are no obstructions in the hopper the fuel will descend freely to the throats l8. In passing through the throats there will be little opportunity for the fuel to become blocked by arching or otherwise, since the wall 2| is vertical and will not provide an abutment for an arch, and the Wall 22 is sufficiently steep to prevent fuel from accumulating thereon and remaining stationary in the absence of arch formation. The downward movement of V the fuel is facilitated by the comparatively unrestricted nature of the throats, which are open at their lower ends for the full width of. the rams and begin to increase in width immediately above the rams.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is;

1. An automatic stoker comprising a series of ram casings, a fuel feeding ram in each ram casing, means to reciprocate the rams in generally horizontal parallel paths, each ram casing being formed with a throat above the ram having two lateral walls, one of said walls in each ram casing being substantially vertical and the other of said walls sloping upwardly and laterally with its upper edge close to the vertical wall on the adjacent ram casing, and a laterally elongated hopper mounted above the ram'casings in a position to deliver fuel by gravity to the several throats.

2. An automatic stoker comprising a series of ram casings, a fuel feeding ram in each ram casing, means to reciprocate the rams in generally horizontal parallel paths, each ram casing being formed with a throat above the ram having two lateral walls, one of said walls in each ram casing being substantially vertical and the other of said walls sloping upwardly and laterally at an angle steeper than the angle of repose of the fuel, with the upper edge of each of, said sloping walls close to the vertical wall on the adjacent ram casing, and a laterally elongated hopper mounted above the ram casings in a position to deliver fuel by gravity to the several throats.

3. An automatic stoker comprising a series of ram casings, a fuel feeding ram in each ram casing, means to reciprocate the rams in generally horizontal parallel paths, each ram casing being formed with a throat above the ram having two lateral walls, one of said walls in each ram casing extending substantially vertically upward from one side of'the ram and the other of. said walls sloping upwardly and laterally from the other side of the ram at an angle steeper than the angle of repose of the fuel, with the upper edge of each of said sloping walls close to the vertical wall on the adjacent ram casing, each throat being open at its lower end for substantially the full width of the ram and widening continuously from its 'lower end upwardly, and a laterally elongated hopper mounted above the ram casings in a position to deliver fuel by gravity to the several throats.

4. An automatic stoker comprising a series of ram casings, a fuel feeding ram in each ram casing, means to reciprocate the rams in generally horizontal parallel paths, each ram casing being formed with a throat above the ram having two lateral walls, one of said walls in each ram casing being substantially vertical and the other of. said walls sloping upwardly and laterally at an angle steeper than the angle of repose of the fuel, with the upper edge of each of said sloping walls close to the vertical wall on the adjacent ram casing, a laterally elongated hopper mounted above the ram casings in a position to deliver fuel by gravity to the several throats, the hopper having a front and a rear wall, and a series of deflectors secured at their ends to the said front and rear walls and located directly above the upper edges ofv each pair of adjacent lateral walls of the throats, each deflector being shaped as an inverted V in crosssection with one vertical leg overlying the adjacent vertical lateral wall and one sloping leg overlying the adjacent sloping lateral wall.

ALBERT G. BLODGETT. 

